It most certainly is. In a club diving environment (my club is CMAS affiliated, but I'd be surprised if BSAC clubs were very different), you're not just assumed, but even expected to plan your dive within your limits, and then do the dive with your buddy - be it a regular one, or your buddy of the day. We don't have guides or DMs in the water, no-one is babysitting us
That's not true for all of CMAS.
FFESSM (France), but in France, the law says (N1,N2,N3,N4 are divers levels, where N4 is basically a dive leader and N1 is like a nothing):
-N1, not allowed to dive by themselves, can go up to 20m with a N4.
-N2, allowed by themselves up to 20m, require a N4 (or more) and is then allowed to 40m.
-N3, allowed byx themselves up to 60m.
-N4, same as N3 but can also guide.
CMAS.ch doesn't seem to have a very different system to this one.
And yes, N2 are allowed to do deco.
Only N4 has requirements on his equipement, which is mainly "you need 2 separate first stages".
None of these levels requires v-drills, Nitrox or anything like that.
Basically: I'm not shocked by some slight deco, it's done all the time in a lot of Europe, and also in some more remote countries, eg Vanuatu.